Block-signal system.



rATnNT clarion.

LAURENCE n. HAWKIN's,.or SCHENCTADY, NEW YORK, AssIGNoR, :BY MESNE As- SIGNMENTS, Tot THE UNIN sWITCH' AND SIGNAL COMPANY, A CCBPONATION 0F PENNSYLVANIA.

nINs, a citizen ofthe United States, resid.

ing at Schenectady, county of Schenectady,

State of New York, have invented certain new and useful Improvements in Block-Slgnal Systems, of which the following is a specification.

My invention. relates to block signal systemsfor railways and consists of a modifica tion of the system disclosed in my companion application, Serial, No. 511,668, filed Aug.

.7, 1909. In that application I disclosed a system in which the signals are arranged to give dan er, caution and clear indications either' y two 2 position arms or by one 3 position arm, and in which the control of the signals is obtained without line. Wires by an arrangement comprising a pair of track relays for each block controllingr the caution and clear indications res iectivcly, cach having two coperating win ings, one connected to the track and lthe other supplied with alternating current independently 'of the track circuits, the currents in the latter windings of the two relays of each pair being'diii'erent in phase, with means controlle'd by a train in one block for shifting the phase ofthe track current in the preceding block so as to energize first one and then both of the track relays of the preceding' block. The principal advantages of that system, as compared with former wireless systems are,rst, that Atrack relays of the most elicient type are employed so that the current consumption is reduced to a minimum; second,that since the relay controlling the caution indication is not even momentarily denergized when the phase of the track current is shifted to energize the relay con` trolling. the clearindication, it islunnecessary to employ a quick acting switch for controllingrthe .phase of the track current; and third, if vthe transformers of adjacent blocks are reversely connected a breaking down of the insulated joint between two adjacent block sections will always cause the relays .adjacent yto those joints to open their contacts so that the signal controlled by them Will he put at stop, thus the false clear indications, which are possible in other wireless systems whenv joints break down, are impossible .in this system. j

' In my companion application I illustrated j Specification of itteistt, application 1aed August 7, 1909. seria-i is 511,694,

BLoei'rslCNas SYSTEM,

Patented Sept. 1Q, 1912.

and described a polypliase transmission system.

In some cases it is not convenient to employ a polyphase transmission, and the 0bject o f my presentinvention 1s to rovide simple and reliable means for shifting the phase of the track current asuflicient amount when the system must be operated with a single phase transmission. In order to make the system positive and reliable,vthe phase of the track current should be shifted through nearly, if not quite, 90. I have found that if a resistance and reactance are provided, each having an impedancey approximately equi to that of the track circuit itself, and if in one :osition of the switch contacts controlling tie track circuit the resistance be 4connected in series withthe source of the,

track current and-the reactance in shunt, and in another position the reactancelpe eonnected in series and the resistance in shunt, the phase ofthe track current will be ,shifted through practically 9() When the cohtacts. move from one position to the other. The exact amount of impedance and reactance required will depend upon the power factor of the `track circuit, but with such a power factor as is likely to be found in practice, the values above-mentioned are approximately correct.

By properly arranging the switch contacts the change from one set of connections to the other may he made without opening the circuit, so that the relay controlling the caution indication is not denergized.

In its broadest aspect, I ny present invention is not limited to the particular rela arrangement of my companion application, but is particularly advantageous for use with that arrangement. 'since power is inevitably wasted iny shifting the phase of the track current and since with tbcrelay arrangement of my companion application, the amount of track current is small so that the amount oipower wasted is correspondingly small. i' A My invention will best be understood by reference to the accompanying drawings,in which- Figure 1 shows my invention, and Figs. 2 to 4 are explanatory vvector. diagrams.Y v l -In Fig. l, A, A 'A2 and As represent the vdiagrainmatically aV block signalsystem arranged in'accordance with 107- rails of four blocks which are shown s'eparated from each other by the customary insulating joints. B'represents an alternating currentgenerator supplying the line i ires b from which current 1s derived for the ignal circuits. C, C and C represent transformers `having their primaries connected to the line wires b andl their secondaries supplying the track circuits A, A and A?,

respectively.` c, c represent resistances, and c', c reactances. D to D represent track rela s. There-are two .of these relays per bloc or track section. T ese are shown diagrammatic-ally as of the two phase induction type, each coxnprisin a short-circuited .member d actuating t e relay .contacts, a winding d connected to thetrack, and a winding d? su plied with alternating current independenti;7 of the track circuit. The windings d of each air of relays are supplied with currents oi)- diiferent. phase. This .phase displacement between the current-s may beobtained in the manner shown by placinga resistance da in shunt to, and` a reactance d* in series with, one winding d2, and a reactance d 1n shunt to, and a resistance d3 in series with, the other winding de,

or any other suitable arrangement for producing a 90 displacement between the currents in the windings d may be em loyed. E', E2 vand Es represent signals or the blocks arranged to give thr e indications, danger, cautiony and clear. have illustrated one-arm three-position signals, but it will be understood that my invention is equally applicable to two-arm two-position signals. e and e represent contacts mounted on the signal shaft'as indicated diagrammatically in dotted lines and e to e' represent stationary contact fingers. These contacts and contact fingers control the hase of the current supplied'to the track circuit by the secondary of the transformer by means of resistance c and reactance c.

The usual contacts for controlling the' signal mechanism, as well as the signal mechanism itself, are omitted from the drawing in order to avoid complication, since many suitable arrangements of mechanism and controlling contacts 'are well known in the art. It will beunderstood that the conductor ledto the lower side of the blade is common to the circuits for caution and clear indications, the circuit extending .directly from the upper side of the blade to the contacts of relay D,-D, or D4 being lthat for the control of the caution indication, and the circuit extending directly to ythe contacts of relay D, D, or D, that for the control of the clear indication. I n accordance with usual practice, that circuit controlling the clear indication is controlled by the caution ition relay (D, D' and D) but it is un erstood that this etrangenosasaa mentof co trol is unnecessary in the normal working of the sys em and is employed only as a precaution to sure the signal moving to danger in case the contacts of the clear position relay should stick in the closed position. l

When a train is in a block, as indicated in block A3, the track windings of both track -relays D4 and D5 aredener ized, so that -the relay contacts are open an the sign al E3 stands at stop. The wmdings d' of the two relays are energized with currents diiferin in phase by approximately 90, as indicate in Fig. 2, 1n which oz" indicates the phase of the current in the winding d2 of relay D* and oz"l the phase of the current in the winding Z2 of relay D". With the signal E4 at stop the contacts e and e are in the positions shown, and it will be seen that the reactance o is in series with the secondary of trans former C2 while the resistance c is connected in shunt to the track circuit. These connections may be traced from the left-hand secondary'terminal of transformer C, through contacts es, e, e, reactance o', to the upper rail of block A2, while the shunt circuit ex' tends from the upper rail to resistance c, contacts e e and c to the right hand secondary terminal of transformer, C', which is connected to the lower rail. The reactance being' in series and the resistance in shunt to the track circuit the connections of the track circuit are similar to those of the winding d2 of relay D2, and if the power factor of the track circuit and of the winding d were the same, the phase of the currents in the windings d and d of relay D would be approximately in phase and the relay would consequently be without torque, if the resistance da and reactance fl* bore the same relation to the impedance of winding a2 that the resistance c and the reactance c' bear to the impedance of the track'circuit. But iu practice the power factor of the track circuit and of the winding d are not the same but may differ by as much as 45. The track circuit is ordinarily of considerably higher power factor than the winding d2, so that the track current is more advanced and does not lag in its phase so muchas the current in the winding t. The conditions in the windings of relays D2 and Da may, consequently, be represented by the vector diagram, Fig. 3, in which 0i and 0i represent the-'currents in the .vindings d2 of the relays D2 and D, as in Fig. 2, the same vectors represented thc-currents in the windings al of the relays D and D, while oz' represents the phase of the track current, displaced approximately 45 froml the currents in t c other windings of the pair of rela s but leading the current in winding d o relay Dz and lagging behind the current in tllc corresponding winding of relay D". This sor 'D' are energized.

displacement of 45 is due to the difference in the power factors of the track circuit and .of the. windings cl2 of the relays, as eX- plained above. If the relays are so vwound or connected that they close their contacts when the current in the track winding leads that in the othe, then relay D2 will close its contacts, as shown, while relay D3 will be held in open-circuited position both by gravity and by a reverse torque in the relay. Relay Da inl closing its contacts closed the circuit from the right-hand secondary terminal of transformer C', 4through the relay contactsv and' through the signal mechanism to the left-hand secondary terminal of the transformer. The signal has accordingly moved from danger to caution position. Tn making this movement the signal shifts contacts e and e to the position shown. The change in connections thereby produced may be understood by comparing the contacts of signal E2 with the contacts of signal E3. Tn moving from one position to the other, the irst change in connections that occurs is opening the circuit of the resistance `c at lthe finger c5, so vthat the resistance which was connected in shunt to the track circuit is open-circuited. 'Next contact e engages contact e, so as to connect the resistance c in parallel with the reactance c. Contact c then leaves contact c2, open circuiting the reactance, andV tinally contact e engages contact e" connecting the reactance in shunt to the track circuitf Thus the transformer C2 has the reactance in series and the resistance in shunt, while the transformer C has the resistance in series and the reactance in shunt, the change being made without opening the connections from the transformer to the track. The result of this change is to advance the phase of the current supplied by trausforn'ier C to the track by about 90, so that the conditions at relays D and D are as shown in the diagram, Fig. 4, the track current 0i being advanced 900, as compared with its position in Fig. 8. The track current now leads the current in windings du of both relays, so that both relays Dv and The relay D closed a circuit which may be traced from the righthand secondary terminall of transformer C, through contacts of relay D, contacts of re' lay D', and through the mechanism of sig nal E to the left-hand transformer terminal, so that the signal E has moved from caution to clear. During this movement the contacts c and @"of this signal have been moved to the position shown, but this movement of these contacts produces no change in the circuit connections.

It will be noted that during the intermediate connections established by the switch contacts, when the signal is moving from stop to caution so as to shift the phase of the track circuit from the position shown in Fig. 3 to that lshown in Fig. 4, the track circuit is never opened and the phase of the current is advanced step by step, first in a direction to increase the phase displacement betweenl the track current and that in the windings d2 of relay D2' and thus slightly to increase the relay torque, and then after this phase displacement has reached 90, to reduce therelay torque again until the phase displacement of 135O is reached, which is the final condition shown in Fig. 4.

It will be noticed that the transformers of adjacent blocks are reversely connected to their track f circuits. This relative reversal of connections has not been mentioned in the preceding description, since the track windings of the relays of the adjacent blocks arc also relatively reversed, so that, so far as norma'l operation of the system is concerned the relative reversal is immaterial. T he reversalbecomes of importance when an-insulated joint breaks down. In this event the current which flows through the broken down joint to the adjacent relays is reversed 180 in phase from the current which normally is supplied to the relays and, therefore, is always of a phase to create a reverse' torque in the relay controlling the movement of the signal from danger to caution. nections of the other relay are carried through this relay, the result is always to put the signal at stop regardless of its position prior to the breaking down of the joint and regardless of the positions of trains. Thus, the same advantage with respect to protection against broken joints is obtained in the present arrangement as is obtainable in the arrangement of my prior applica-tion.

I do not desire to limit myself to theparticular arrangement of parts shown and described, but aim in the appended claims to cover all modifications which are within the scope of my invention.

What I claim as new and desire to secure by Letters Patent of the United States, is,--

l. 'In a block signal system, signals for the blocks adapted to indicate danger, caution, and clear, track circuits including sources of alternating currentI for the blocks, a pair of track relays for each block having windings included in the track circuit and controlling the caution and clear indications according as one or bot-h relays are ener` gized, a resistance and a reactance for each source, and connections including switch contacts controlled by a train in one block controlling the circuit .of the source for the preceding block arranged in one position to connect the resistancein series and the reactance in shunt to said circuit and in another position to connect the reactance in series and the resistance in shunt to said Since the contact conl circuit) one of the track relays of said preceding block being res onsive-to current from said source with eit er ofsaid connectionsv an the' other to currentfrom said source 'th one lconnection only.

2.,.In a block signal system, signals for the' blocks adapted to indicate danger, caution and clear, track circuits including ygnurces of alternating current or the blocks, 'x air ot track relays for each block controlling the caution and clear indications, according as one or both relays are enerize each of said relays having a winding lnclLded in the track circuit and a second co erating winding supplied with alternatin current independent-ly of the track circuits, the currents supplied to said second windings differing in phase in the two relays of each pair, a resistance and a reactance for each source, and connections 1ncluding switch contacts controlled by a train in one block controlling the circuit of the source for the preceding block arranged in one position to connect the resistancein series and the reactance in shunt to said circuit and in another-position to connect the reactance in series and the resist-ance in shunt to said circuit.

3. In a block signaltsysteni, signals for the blocks adapted to indicate danger, caution and clear, track circuits including sources of alternating current for the blocks.l a pair of track relays for each block having windings includedin the track circuit and controlling the caution and clear indications according as one or both relays are energized, a resistance anda reactance for each source, and connections including switch contacts controlled by a train in one block controlling' the circuit of t-he source for the preceding block arranged in one lposition to connect the resistance inseries and t-he re-A actance in shunt to said circuit and in another position to connect the reactance in4 series and the resistance in shunt to said circuit, the contacts which establish the series connections of the reactance being varranged to close before thc contacts which break the series connection of the resistance open, one of the track relays ofsaid preceding block being responsive to'current from said source with either of said. conncctions and t-he other to current from said source with one connection only..

4. In a. block signal system, signals for the blocks adapted to indicate danger, caution and clear track circuits including sources of alternating current for thc blocks, a pair of track relays for each block con` trolling the caution and clear'indications" according as one or both relays are energized, cach of saidrelays having a winding included in the track circuit and a second coperating winding supplied with alternatlng current independently ofthe track circuits, the current sup lied to said second windings differing in p ase'in the two relays of each pair, a resistance and a rcact,-

ance for each source, and connections including switch contacts controlled by a train in one vblock controlling the circuit of. the source for the preceding block arranged in one position to connect the resistance in series and the reactance in shunt to said circuit and in another position to connect the reactance in series and the resistance inY shunt to said circuit, the contacts which establish the series connections of the reactance being arran ed to close before the contacts which brea the series connection of the resistance open.

5. In a block signal s stem, signals for the blocks adapted to in icate danger,'cau tion and clear, track circults includingY sources of alternating current for the blocks, a pair of track relays for each block havin"i windin s included 1n the track circuits and control ing the caution and clear indications according as one or both relays are energized,A a resistance and reactance for each source, and connections including switch contacts controlled by the movement of a signal from danger to caution controlling` the circuit of the source block arranged in one position to connect the resistance in series andthe reactance'vin shunt to said circuit and in another osition to connect the reactance in series an the resistance in shunt to said circuit, one' of the track relays of the preceding block being responsive' to current from vsaid source with either of said connections and the other to current from said source with one connection only.

6. In a block signal system, signals for the blocks adapted to indicate, danger, caution and clear, t-rack circuits including sources of alternating current for the blocks, a pair of'track relays for each block controlling' the caution and clear indications according as one or both relays are energized, each of said relays having a winding included in the track circuit and a second cooperating winding supplied with alternating current independently of the track circuits, the currents supplied to'said' second windings vdiffering in phase Vin the two relays of each pair, a resistance and a reactance for each source, and connections including switch contacts controlled by the movement of a signal from danger to caution controlling the circuitkof the source for the preceding block arrarged in one posifor the preceding tion andA clear, track Qlcuits. .including sources of alternating current for the blocks,

a pair of'track relays for each block having windings included in the track circuit and controlling the caution and clear indicatiQItS,

according as one or both relays are ener .sistance in shunt to said circuit, the contacts which establish the series connections of the reactance being arranged to close before the contacts which break the series connection of the resistance open, one of the track relays of the preceding block being responsive to' current from said soul-C6 With either of said connections and the other to current from said source with one connection only.

8. In a block signal system, signals for the blocks adapted to indicate danger, caution and clear, track circuits for the blocks, a single rphase transmission system extending along the roadway, a pair of track relays for each block controlling the caution and clear indications according as one or both relays are energized, each relay having two coperating windings, one connected to the track circuit of the block and the other supplied from the transmission system independently of the track circuits, means for producing a difference of phase between the currents in the last-mentioned windings of each pair of relays, a transformer for each block having its primary supplied from said transmission system and its secondary connected to the track circuit of the block, and means controlled by a train in the block in advance for controlling the phase of the current supplied bysaid transformer to the track circuit.

9. Ina block signal system, signals for the blocks adapted to indicate danger, caution and clear, track circuits for the blocks, a single phase transmission system extending along the roadway, apair of track relays for each block controlling the caution and clear indications according as one or both relays are energized, each relay hav ing two cooperating windings, one connected to the track circuit of the block and the other supplied from the transmission system .independently of the track circuits, means for producing a difference of phase between the current-s in the last-mentioned windings of each pair of relays, a transformer for each block having its primary supplied from said transmission system and its secondary connected to the track circuit of the block, phase shifting `means in circuit with said transformer, and connections including switch contacts controlled by a train in the' block in advance in circuit with said transl.

vformer and said devices for controlling the 0 Vphase of the current supplied by said trans;

former to -the track circuit.

10. Ina block signal system, signals for* the blocks adapted to indicate danger, cau# tion and clear, track circuits for the blocks,

a single phase transmission system extend-p ing along the roadway, a pair of track relays for each block controlling'the caution and clear indications according as one or both relays are energized, each relay having. two

coperatin windings, one connected t the l track circuit of the block and the other supplied froin the transmission system independently of the track circuits, means for producing a difference of phase between the circuits in the last-mentioned windings of` each pair of relays, a transformer for each block havingits primary supplied from said transmission system and its secondary con.

nected to t-he track circuit ofI the block,

phase shifting means in circuit with said transformer, and connections including switch contacts controlled by the signal next in advance operated upon the movement of said signal from danger to caution and arranged to vary the connectionsof said devices to vary the phase of the currentsupplied by said transformer to the track cir-' cuit. l i

11. In a railway signaling system, a track circuit, a source of alternating signaling current for the track circuit, a resistance and a reactance, means independent of the track circuit for connecting the resistance in series and the reactance in shunt with the track circuit and for connecting thc reactance in series and the resistance in shunt with the track circuit; and two relays connected with the track circuit, one ofl which is responsive to current from the said source with either of said connections and the other of which is responsive to current from said source with one only of said connections.

12.' In a railway signaling system, a track circuit, a source of alternating signaling current for the track circuit, a resistance and a reactance, means independent of` the track circuit for connecting the resistance in series and the reactance in shunt with the track circuit, andor connecting the reactance in alternating signaling current independently 1125 of the track circuit, the currents supplied to said second windings diiiering in phase whereby one of the relays is responsive to current from the said' source with either of said connections and the other relay is respcnsive to' current from said source withl :ix resistance in series with thesecond winding 15 one only of the said connections.

.13. Ina railway signaling system2 a track circuit, a source of alternating slgnalingI current, two relayseach having a windin included 1n the track circult and a secon coperating winding supplied with alter-l nating signaling current independently of the track circuits; means for causing `the currents supplied to the two said second windings to differ in phase, said means comprising a` resistance m shunt to and a re actance in. series with the second Winding of one relay, and a reactance in shunt to and cfgthe -ether relay; and means for -su plyin currents of t-wo different phases to t e trac circuit from the said source, one ofthe relays being responsive to track circuit current of` either of said phases and the other relay being responsive to track circuit current f one only of said hases.

In witness whereof,` I ave hereunto set my hand this 5th da of Au ust- `1.909.

' LAURE CE A,gH iVitnesses:

BENJAMIN B. HULL, EDWARD WILLAMs. 

